Why Twin Screw Pumps Are a Top Choice for Sanitary Processors
Precise tolerances and the ability to pump a wide range of viscosities and temperatures, partnered with an extremely low cost of ownership make twin screw pumps a top choice for sanitary processors in food, beverage, personal care and other high purity industries.
Twin Screw pumping technology has existed for a century, but was originally developed in the oil & gas industry. At the end of the 20th century Jung Process Systems helped to develop the first sanitary, twin screw positive displacement pump that was both EHEDG and 3A compliant. The versatility, flexibility and optimal performance have positioned twin screw pump technology as an industry leader for processors with tough pumping applications.
TWIN SCREW PUMP ADVANTAGES FOR SANITARY PROCESSING
One Pump = Two Duties
Twin screw pump technology is the ONLY type positive displacement pump that has the ability to run up to 4,000 RPMs. This means, that unlike any other PD pump, a single twin screw pump can perform both process and CIP. This gives processors the ability to eliminate additional CIP return pumps, bypass valves and all of the excess controls.
Wide Range of Viscosities
For viscous products, twin screw pumps can run at a relatively low speed to be gentle and provide a very high suction capability. On thin, water-like products, the Axiflow pump can be sped up to overcome the slip to maintain high velocities to perform CIP and CIP return pump functions. This ability to change from very thin to very thick liquids with the same pump is a great way to reduce the number of pumps in any one plant.
Extreme Speed Range = Long Product Life
As rotary lobe (RL) and circumferential piston (CP) pumps wear, the pump’s suction capability is greatly reduced, and the only way to achieve the same output is to increase speed. However, speed can only be increased so much. But with the widest range of speeds, twin screw pumps are able to be sped up to overcome slip. This increase in speed does not diminish its ability to pull a good vacuum. Therefore, you get much more useful life out of a set of screws than you would out of a set of rotors.
Ability to Run Dry
Much like progressive cavity (PC) pumps, twin screw pumps have the same high suction capability, both are lower shear pumping devices, both are capable of handling large soft solids and both provide a smooth, virtually pulse free delivery of product. Where twin screw sets itself apart is in its ability to run dry for hours. Twin screw pumps can pump up to 60% air and it will never air-lock. The symmetrical screws do not require product to stabilize the rotor, meaning there is no overhung load to cause contact between the rotor and the housing.
Twin screw pumps are also incredibly versatile. By simply switching to a different screw pitch, you can change the entire flow curve on the pump. For instance, a tighter screw pitch is capable of higher pressures but lower flowrates. A larger screw pitch enables a pump to perform higher flowrates at lower pressures and much lower shear rates, while pumping larger soft solids.
Tight Tolerances for Extreme Temperatures
Axiflow is the most successful Sanitary Twin Screw PD pump in North America. It sets itself apart from other twin screw pump offerings by providing a wet end and gearcase/bearing housing that is completely machined out of 316L billet stainless steel, straight through the entire bearing housing without being removed from the five axis machine. This ensures the most precise tolerances and the ability for the entire pump and bearing housing to expand and contract together at the most extreme of temperatures.
Low Cost of Ownership
Compared to the rest of the industry, the Axiflow twin screw pump:
- pumps the widest range of product viscosities (1 to 1,000,000 cps)
- operates at the widest range of pump speeds (up to 4,000 RPMs)
- operates at the widest range of product temperatures (up to 425°F)
- offers high suction capability
- has the ability to run dry for hours
- offers low shear pumping capability
- handles delicate soft solids up to 1-5/8”
- delivers a smooth, non-pulsing, repeatable product flow
These capabilities greatly reduce the wear on the pump and cost/need of spare parts. This is why Axiflow pumps are proving to be the Lowest Total Cost of Ownership (TCO) for PD pumps.
The Axiflow sanitary, twin screw, positive displacement pump is changing the way companies look at their process pumps. Check out how twin screw pumps stack up versus the competition by downloading our pump comparison chart.